1. Field of the Invention
The present invention relates to diagnosing and screening for sleep disorders, such as obstructive sleep apnea (OSA), and, in particular, to an apparatus and a method for collecting data for a sleep study for diagnosing and screening for a sleep disorder wherein a status indicator is provided to indicate to the user whether enough valid data for the study has been collected.
2. Description of the Related Art
Obstructive sleep apnea (OSA) is a condition in which sleep is repeatedly interrupted by an inability to breathe due to an obstructed upper airway segment. Those afflicted with OSA experience sleep fragmentation and complete or nearly complete cessation of ventilation intermittently during sleep with potentially severe degrees of oxyhemoglobin desaturation. These symptoms may be translated clinically into extreme daytime sleepiness, cardiac arrhythmias, pulmonary-artery hypertension, congestive heart failure and/or cognitive dysfunction. Other consequences of OSA include right ventricular dysfunction, carbon dioxide retention during wakefulness, as well as during sleep, and continuous reduced arterial oxygen tension. Hypersomnolent sleep apnea patients may be at risk for excessive mortality from these factors as well as by an elevated risk for accidents while driving and/or operating potentially dangerous equipment.
OSA can only be diagnosed by a sleep study. A sleep study may be performed at a sleep lab using sophisticated equipment under the direction of a clinician. Such studies are commonly referred to as an “attended” sleep studies due to the presence of the clinician. Some people, however, find it difficult to sleep when hooked up to the numerous wires and sensors required by the sleep lab equipment and/or under the watchful eye of a clinician. Alternatively, a sleep study may be conducted by a patient outside of a sleep lab (commonly referred to as an “unattended” sleep study) using a portable data recorder that collects data relating to certain parameters of the patient while the patient is sleeping (typically overnight). The collected data is then used by a clinician to determine whether the patient has OSA.
A proper sleep study requires that a certain amount of valid data be collected from the patient. In addition, Medicare reimbursement guidelines define a “Sleep Study” to be: “simultaneous recording of ventilation, respiratory effort, ECG or heart rate, and oxygen saturation” while “attended” or “unattended” by a “technologist.” The guidelines also state that “[s]leep studies and polysomnography refer to the continuous and simultaneous monitoring and recording of various physiological and pathophysiological parameters of sleep for 6 or more hours with physician review, interpretation and report.” These guidelines are used by most private payors as well. In the case of an unattended study, in order to assess whether enough valid, quality data has been collected during the study, the data must be downloaded from the portable data recorder that was used to a clinician's external computer so that it can be analyzed.
Current portable data recorders, however, typically offer limited feedback to the patient. Thus, if a sleep study is conducted unattended in a patient's home, the patient will not know whether sufficient valid data has been recorded until the portable data recorder is returned to the clinician and the data is analyzed. If the recorded data is not sufficient/acceptable, the portable data recorder must be reconfigured and returned to the patient so that another study can be performed. This process will be time consuming and inconvenient to the patient and may discourage the patient from taking the time required to complete a valid sleep study. In addition, the need to repeat sleep studies due to insufficient data places an additional financial burden on the healthcare system. Thus, there is a need for an apparatus that determines whether sufficient valid data has been collected during a study and provides an indication thereof to the patient.